This disclosure relates to imaging systems and methods, and, in particular, to imaging systems and methods in which the depth or field (DOF) is extended or increased.
The depth of field (DOF) of an imaging system is the range of distance in which an object can be positioned with respect to the imaging system such that an image of the object is sharply focused. Depth of focus refers to a range of distances that a detector can be from the imaging optics, such that an object at a given distance is sharply focused. Therefore a range of depth of focus can be considered to map to a corresponding depth of field. A typical optical imaging system has a limited DOF. When the imaging system captures optical data, i.e., takes a picture, only objects within the depth of field will have sharp images in the picture. The adjustment of the system to produce a sharp image of an object at a particular distance from the imaging lens is commonly known as “focusing.” It is desirable to extend the DOF of imaging systems such that images of objects having varying distances appear sharp in the picture. Extended DOF thus allows a photographer to be less concerned about focusing on a particular object.